function click_back(){
    window.location.href='首页.html';
}

function click_download() {
    var div_l=document.getElementById("app");
    var div_r=document.getElementById("wechat");
    if (div_l.style.left != '0px')
    {
        console.log(div_l.style.left);
        div_l.style.left='0px';
        div_r.style.right='0px';
        div_l.style.transition='all 0.2s cubic-bezier(.25, .1, .25, 1)';
        div_r.style.transition='all 0.2s cubic-bezier(.25, .1, .25, 1)';
    }
    else
    {
        console.log(div_l.style.left);
        div_l.style.left='-250px';
        div_r.style.right='-250px';
        div_l.style.transition='all 0.2s cubic-bezier(.25, .1, .25, 1)';
        div_r.style.transition='all 0.2s cubic-bezier(.25, .1, .25, 1)';
    }

}